SACRAMENTO, Calif. (AP)  California’s death row inmates could be executed using one of four different drugs or choose the gas chamber under regulations submitted for final approval Friday, just days before state voters consider whether to do away with the death penalty or reform it.

The plan by corrections officials responds to court pressure and amid a nationwide shortage of execution drugs.

The Office of Administrative Law now has 30 working days to review the regulations for technical problems. If approved, the rules could go into effect early next year, barring court challenges.

California has 750 condemned inmates on the nation’s largest death row. However, the state hasn’t executed anyone since 2006 and frustration over the law and the endless appeals that go with it spawned competing initiatives on Tuesday’s ballot.

Proposition 62 would end the death penalty and keep condemned inmates in prison for life. Proposition 66 would speed up appeals and let officials begin single-drug executions.

The regulations submitted Friday would let corrections officials choose between four powerful barbiturates  amobarbital, pentobarbital, secobarbital or thiopental  for each execution, depending on which one is available. Inmates also could continue to choose the gas chamber for their execution.

Eight states have used a one-drug method, according to the nonprofit Death Penalty Information Center, which opposes executions and tracks the issue. Five states in addition to California have announced plans to use a single drug but have not done so.

Executions in California stalled amid legal challenges after 76-year-old Clarence Ray Allen was put to death with three drugs in 2006 for ordering a triple murder.

Federal and state judges suggested the state could resume the punishment if it began using a single drug, prompting Gov. Jerry Brown to say in 2012 that California would consider a one-drug lethal injection.

But there was little progress on the change until a judge forced the state’s hand with a ruling last year.

The American Civil Liberties Union of Northern California said two of the four drugs identified in the state proposal have never been used in executions.

It also questioned whether the drugs will be safe and effective, since the Department of Corrections and Rehabilitation plans to have the one used for each execution specially made.

The department “is engaging in nothing less than human experimentation,” Ana Zamora, the ACLU’s criminal justice policy director, said in an email.

About 36,000 people submitted about 167,000 individual comments on the new regulations, department spokeswoman Terry Thornton said.

The department tried to adopt regulations for a three-drug method in 2009 and 2010, but the attempts were blocked by a judge in 2012.

Matt Cherry, director of the campaign to eliminate the death penalty, said the “arduous legal battle over California’s broken death penalty system” is another reason for voters to eliminate it.

Michael Rushford, president of the Sacramento-based Criminal Justice Legal Foundation, also expects more bureaucratic and legal challenges to stall executions. The foundation sued to force corrections officials to adopt the new rules.

Proposition 66 would speed things up by eliminating the need for the department to continue the usual administrative process, he said, speaking for the pro-death penalty campaigns.

Opponents already have signaled they are likely to challenge the regulations in court, meaning more delays are likely before anyone is executed if voters keep the death penalty.